HACKENSACK, N.J. — For a newcomer driving through this landlocked city in suburban New Jersey, a short drive from Manhattan, it is an unexpected sight.

Just off River Street, behind the New Heritage Diner, it looms like something out of the Battle of Midway: the U.S.S. Ling, a World War II-era submarine longer than a football field, squatting in a shallow stretch in the upper reaches of the Hackensack River.

This 312-foot hulk of gray steel has been berthed along the river’s shoreline since the early 1970s, when the Navy offered it to a group of local veterans. They were looking to use it as the theme of a new naval museum with the help of the owners of The Record of Bergen County, whose headquarters long stood on this riverside property.

But the Ling has become a 2,500-ton problem, on course to be torpedoed by a luxury development project.

The vessel was originally towed up the river, thanks to a dredged channel deep enough to accommodate barge traffic. But the river has steadily filled in with silt, leaving the submarine mired in the muck.

Then came a battering by Hurricane Sandy in 2012, leaving the sub inaccessible and the museum’s future shaky.

But the death blow for a vessel built to face German U-boats may come from, of all things, the decline of the newspaper business.

Faced with revenue losses, the Borg family, which long owned The Record, sold its publications to the Gannett newspaper chain last year. Now the family is redeveloping the 20-acre property and wants the unsightly Ling out.

The problem is, no one seems to know what to do with it, or even how to move it, whether for restoration or scrap.

The group of military veterans that runs the naval museum wants to restore the sub as an attraction but sees no help on the horizon. They have no money to even replace the gangplank on the Ling, the only remaining high-speed submarine from World War II.

No one else seems to consider the Ling their responsibility — not the Navy or any governmental entity, and certainly not the Borg family.

“It’s not on our property — it’s in the river and we don’t own the river,” said Malcolm A. Borg, 79, former chairman of The Record whose father, Donald G. Borg, helped obtain the sub when he was editor and publisher.

“He thought it would be a wonderful attraction,” Malcolm Borg said of the now-languishing vessel.

“Its tragic — it’s rusting through in a number of places,” he said. “It would take a lot of permits to get that boat out of there. It’s stuck in the mud.”

Les Altschuler, vice president of the Submarine Memorial Association, which runs the New Jersey Naval Museum, said his group was still active and controlled the vessel but had neither the money nor the ability to move the Ling, especially since the museum had to close, curtailing revenue from admission fees and small donations.

“We tried a GoFundMe and barely got $25,” he said of the fund-raising website. “Nobody cares about it.”

Mr. Altschuler, who said he trained on the Ling in the early 1960s while in the Navy, said it needed at least 17 feet of water to be moved. These days, people could traipse through the muck to the vessel at low tide. Mr. Altschuler said that the vessel was still buoyant but that he had been told by government officials that there was scant chance of the river being dredged again.

“We’re caught between a rock and a hard place,” Mr. Altschuler said. “We have no plans to move it because there is no way to move it. There’s not enough water in the river and you can’t get the bridges to open.”

With the area around the sub too shallow for work boats to approach, even cutting up the sub and removing it would be a mammoth task that would require environmental permits, he said.

Mr. Altschuler said a flotation could be built around the vessel and it could be extricated from the mud with a method known as a cofferdam and restored at the site. But even if he could replace the gangway and begin refurbishing the vessel, “if we’re thrown off the property, what access do we have to the boat then?”

Bob Sommer, a spokesman for the Borg family’s development company, Fourth Edition, said the Borgs planned to partner with a developer for a five-year project whose first phase would be a building with 200 rental apartments that could break ground next year. Future phases could include 300 more rental units, retail space and a hotel.

The Ling, named for a type of fish, was launched toward the end of World War II but never saw combat. It was later used for training on the Brooklyn waterfront before becoming the centerpiece of the New Jersey Naval Museum, whose offices and displays were in several trailers.

Several vessels and artifacts outside the trailers that were on loan were reclaimed recently by the Navy, but not the Ling, which the Navy deems to be property of the museum.

As for the remaining torpedoes, monuments and other artifacts languishing on the overgrown property, the Borgs have asked the museum association to remove them, and they have offered help with that, Mr. Sommer said. The museum’s modest memorial, honoring Navy submariners who died in World War II, will be permitted to remain, he said.

And so the days seem numbered for this unheralded museum, which, despite being tucked away and doing little advertising, managed to attract hundreds of thousands of visitors over the years.

Tours of the sub included sitting at the galley tables, peeking into the tiny showers and toilets and views of the torpedoes and the engine room, the dated control panels and the crew’s bunks.

The periscopes in the conning tower would offer views of the concrete plant across the Hackensack River, which cuts through suburban New Jersey just west of New York City roughly parallel to the Hudson River and drains into Newark Bay leading to New York Harbor.

The museum regularly hosted Pearl Harbor Day and other memorial events, and local residents considered it a beloved part of Hackensack, said Albert Dib, city historian and director of redevelopment for the City of Hackensack.

“A lot of us around here associate the Ling with Hackensack, and there’s definitely sentimental attachment,” he said. “But it’s outside the city’s purview to use public funds for something that has always been a nonprofit, private enterprise.”

“We appreciated the significance of the site,” he said, “but it’s become a liability at this point, and that’s a shame.”